Remote perforating in dual completion wells

ABSTRACT

Method for perforating in a dual, parallel pipe string tubingless well. A crossover passage or port connects these pipe strings. Each pipe string is provided with a landing nipple at about the same depth below the crossover port. A radioactive source tool, which includes a radioactive pill for transmitting radiation in angular directions and a seating member for seating the radioactive source tool in the landing nipple arranged in one of the pipe strings, is pumped through the one pipe string until the seating member is landed in the landing nipple. The radioactive pill is suspended from the seating member a predetermined distance which is approximately the level at which it is desired to perforate. A perforating assembly, which includes a directional perforating gun, a directional radiation detector, a radioactivity-sensitive gun-firing mechanism including a source of electrical power for causing actuation of the perforating gun, a rotation device for causing the perforating gun to rotate, a seating member for seating the perforating assembly in the landing nipple arranged in the other pipe string, and a locomotive device for moving the perforating assembly through the other pipe string, is then pumped through the other pipe string until the seating member lands in the landing nipple. The detector of the perforating assembly is suspended a predetermined distance from the seating member so that it is positioned at the same level as the radioactive pill in the adjacent pipe string. The firing mechanism utilizes a switch which is actuated when the radioactive count detected by the radiation detector reaches a predetermined level. The directional gun is aimed so as to fire in a predetermined angular direction when the directional detector is facing the radioactive pill. The perforating assembly is rotated by circulating fluid in the pipe strings. After the perforating gun has fired, the perforating assembly is removed from the other pipe string. The radioactive source tool is then removed from the one pipe string. The perforating gun may be reloaded and the perforating procedure repeated at a different level in the well bore after repositioning the radioactive source tool and perforating assembly.

FIP -Oll Primary Examiner-David H. Brown Attorneys-Thomas B. McCulloch,Melvin F. Fincke, John S.

Schneider, Sylvester W. Brock,-.lr., Kurt S. Myers and Timothy L.Burgess nipple arranged in one of the pipe strings, is pumped throughthe one'pipe string until the seating member is landed in the landingnipple. The radioactive pill is suspended from the seating member apredetermined distance which is approximately [72] inventors MVLCIderslasAn eles; Carlhleitkllhmbothof, Cl. [21] AppLNo. 837,248 [22] Filed27,1969 [45] Patented 24,1971 [73] Assignee Emol'rohetiaalcecehcoqny[5'4] REMOTEPERFORATINGIN DUAL COMPLETION WELIS IOChldDr-awhgib.

[52] USJ 166/297, 166/250, 166/55.1,l75l4.51 [51] H "K216431119 [50]FisldofSearei 166/297, 313, 250, 255, 55.1; 175/451.

[56] Releru'seesClterl UNITEDSTA'I'ESPA'I'EN'IS 3,032,107 5/1962 Rumbleetal 175/451 3,097,693 7/1963 'l75/4.51X 3,208,533 9/1965 166/313X3,294,163 12/1966 l75/4.51X 3,426,851 2/1969 Arendt l75/4.51X

the level at which it is desired to perforate. A perforating assembly,which includes a directional perforating gun, a directional radiationdetector, a radioactivity-sensitive gunfiring mechanism including asource of electrical power for I causing actuation of the perforatinggun, a rotation device for is then pumped through the other pipe stringuntil the seating member lands in the landing nipple. The detector ofthe perforating assembly is suspended a predetermined distance from theseating member so that it is positioned at the same level as theradioactive pill in the adjacent pipe string. The firing mechanismutilizes a switch which is actuated when the radioactive count detectedby the radiation detector reaches a predetermined level. The directionalgun is aimed so as to fire in a predetermined angular direction when thedirectional detector is facing the radioactive pill. The perforatingassembly is rotated by circulating fluid in the pipe strings. After theperforating gun has fired, the perforating assembly is removed from theother pipe string. The radioactive source tool is then removed from theone pipe string. The perforating gun maybe reloaded and the perforatingprocedure repeated at a different level in the well bore afterrepositioning the radioactive source tooland perforating assembly.

PATENTED M1824 IHH SHEET 1 [IF 3 G-2A. FIG-2B.

FIG.

&

5 0 M: m 2 B 6 :IHI w 3 N INVLNIURS THOMAS W. CHILDERS, CARL E.REISTLE,]I[, i -6 ATTORNEY.

PATENTEU AUB24|971 3.601; 196

sum 2 OF 3 F' I G 2 D R fi k v m I 0 o l/ FIG.2C

THOMAS w. CHILDERS, CARL E. REISTLEJII, %/WZM u- ATTORNEY.

REMOTE PERFORATING IN DUAL COMPLETION WELLS BACKGROUND OF THE INVENTIONThe present invention concerns method and apparatus for completingparallel, dual-string tubingless oil and/or gas wells which have throughfiowline (TFL) servicing capability. Tubingless TFL completions haveapplication to underwater wells, highly deviated offshore wells drilledfrom platforms, deviated wells drilled from urban drill sites ordeviated wells drilled from land'to adjacent underwater reservoirs. Oneof the problems in completing such wells is to orient properly aperforating gun in one of the pipe strings so as not to shoot in theadjacent parallel pipe string. The ability to perforate using pumpdowntechniques facilitates completion of subsea wells, as well as futureworkovers. In such wells, it is possible to move the drilling rig offlocation several days earlier than would be the case if the drilling rigwere required to perform well-completion operations.

SUMMARY OF THE INVENTION A method for perforating in a tubingless TFLwell containing two spaced-apart parallel pipe strings comprisinglaunching into one of said pipe strings a radioactive source; pumpingsaid radioactive source through said one pipe string to adjacent a leveltherein at which it is desired to perforate; launching into said otherpipe string a perforating tool provided with a perforating gun having aselected direction of perforation, a detector of radiation having aselected direction of radiation detection relative to said direction ofperforation, means for rotating said perforating gun when theperforating tool is caused to move by hydraulic pressure, a locomotivedevice for causing the perforating tool to move through and in the otherpipe string by hydraulic pressure, a radioactivity sensitive firingmechanism including a source of electrical power for actuating theperforating gun and a switch actuated when the radioactive countdetected by the radiation detector reaches a predetermined level;pumping the perforating tool through the other pipe string until theradiation detector is at the level of the radioactive source; moving theperforating tool by circulation of fluid through said pipe strings tocause said perforating gun to rotate until at one horizontal angularposition of said perforating gun the detected radiation reaches apreselected level to indicate that the direction of detection ofradiation is toward said radioactivesource and said direction ofperforation is in a preselected direction, the perforating gunautomatically firing or actuating when in such position. After theperforating gun has fired, the perforating tool is first circulated outof the well and then the radioactive source is circulated out of thewell.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a cross-sectional view of theearths surface showing a subsea borehole having arranged in it two pipestrings, one of which contains a perforating tool assembly and the otherone of which contains a radioactive source tool positioned in accordancewith the teachings of the invention;

FIGS. 2A-2F illustrate stepwise the perforating procedure for use intubingless TFL completed wells;

FIG. 3 is a partly sectional view illustrating one embodiment of aperforating tool assembly rotating device;

FIG. 4 is a partly sectional view illustrating another embodiment of aperforating tool assembly rotating device;

FIG. 5 is a partly sectional view of still another embodiment I FIG. 9schematically illustrates the firing mechanism circuit in which anovertravel switch is included.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, there isshown a borehole 10 penetrating a subsurface oilor gas-productiveformation 11. Two eccentric parallel spaced-apart pipe strings 12 and 13are arranged in borehole 10 and cemented therein by means of cement 14.Pipestrings l2 and 13 are connected together by crossover port 15. Pipestring 12 is provided with a landing nipple 16 below crossover port 15and pipe string 13 is provided with a landing nipple 17 at about thesame level. A radioactive or nuclear source tool 18 is located in pipestring 12. The components of this tool include a radioactive pill 19suspended at a preselected depth from landing nipple 16 to nearformation 11 on a line or small-diameter flexible tubing 20 attached toa locating lockdown mandrel 21 provided with a seating shoulder 22 forseating in landing nipple 16, a

packoff 23 for sealing off the space between the interior sursealing offthe space between the interior surface of the landing nipple and theouter surface of mandrel 29, and retractable, shearable lugs 32 forlocking mandrel 29 in landing nipple 17. Mandrel 29 also contains therotating mechanism which in this instance is the embodiment shown inFIG. 3 and described later herein. Perforating tool assembly 26 alsoincludes a battery case 33 which is suspended from mandrel 29 by meansof aline or small-diameter line flexible tubing 34. Battery case 33contains electrical power to actuate firing head 35 which in turndetonates fixed directional perforating gun elements 36. A nuclear orradioactive source (radiation) detector 37 is positioned between theelectrical power in battery case 33 and electrical firing head 35.Tubing 34 and tubing 20 are cut to suitable lengths to locate radiationdetector 37 and radioactive source pill 19 at the same depth level inthe well. Radiation detector 37 has a shielded window 38 which allowsthe radiation detector mechanism only to investigate in effect theradioactive count in a small horizontal angular range when battery case33, radiation detector 37, firing head 35 and directional perforatinggun elements 36 are rotated in a circle by means of the rotatingmechanism. The function of the radiation detector 37 is to investigatethe level of radiation of the borehole as it is being rotated around ina circle; and when the radioactive count reaches a preset level,indicating that the radiation detector window is directly facingradioactive source pill 19, a switch makes electrical connection betweenbattery case 33 and firing head 36, which in turn detonates directionalperforating gun elements 36 which are shown facing directly away frompipe string 12. A swivel 39 connects locomotive device 27 to the othercomponents of the tool.

Any desired radioactive substance may be employed as the radioactivepill, such as radon, radium bromide, radium chloride, uranium bromide,uranium tetrabromide, etc. These are naturally radioactive substances;however, other artificial radioactive substances also may be employed.

Radiation detector 37 may be any device capable of converting radiationenergy transmitted from the radioactive source to electrical pulses andwhich transmits said electrical pulses only when the radiation detectedby said detector reaches a specified predetermined level. Suitable foruse is a Gieger-Mueller counter or an ionization chamber or aproportional counter, each modified to transmit electrical signals onlywhen the predetermined radiation peak is reached.

The shielding material on the detector is formed of radiation absorbingor moderating substances, such as lead, tungsten, paraffin, boron,cadmium, etc., which substances are capable of absorbing or moderatingthe detected radiation.

One type of mechanism for rotating the perforating gun elements 36 isillustrated in FIG. 3. Referring to FIG. 3, there is shown a splinedkeyway 40 connected through mandrel 29 by means of shaft 41 and chuck 42to flexible tubing 34. A coiled band spring 43 is connected to shaft 41.A splined shaft 44 is initially arranged in splined keyway 40. A support45 is attached to splined shaft 44 and a compression spring 46 isattached at one end to the support and at the other end thereof to theupper interior end of mandrel 29 to inhibit upward movement of splinedshaft 44. The upper end of splined shaft 44 is connected to locomotivedevice 27 through swivel 39. This rotating mechanism operates asfollows. Mandrel 29 is set in landing nipple 17 and fluid is circulateddown pipe string 12 through crossover port 15 and up pipe string 13.Swab cups 28 are forced upwardly which causes connected splined shaft 44to move upwardly against the bias of spring 46 until splined shaft 44 isno longer engaged in splined keyway 40. Coiled band spring 43 thencauses slow rotation of shaft 41 which in turn rotates tubing 34 andradiation detector 37 and gun elements 36 in one or more completerevolutions.

Another embodiment of the rotating mechanism, illustrated in FIG. 4,includes a splined keyway 50 connected to the rotatable components bymeans of shaft 51. A splined shaft 52 is keyed into splined keyway 50and is initially prevented from vertical movement in the keyway by shearpin 53 which connects keyway 50 and shaft 52. A threaded shaft 54connects shaft 52 to swivel 39 and locomotive device 27. Shaft 54extends through a threaded headnut 55. In operation of this embodiment,fluid is circulated down pipe string 12. through bypass 15 and up pipestring 13 to force swab cups 28 upwardly. Movement of swab cups 28upwardly moves shaft 54 upwardly through threaded headnut 55 to causeshear pin 53 to shear and permit shaft 52 to rotate keyway 50 and shaft51 connected to keyway 50 through one or more revolutions.

The rotating mechanism shown in FIGS. and 6 is a racheting sawtootharrangement. As seen in these figures, a rotatable shaft 60 extendsthrough the lower end of mandrel 29 and connects to the rotatable gunelements. The upper end 65 of shaft 60 which is square shaped extendsthrough a collar or sleeve 61 and is slidably arranged within a hollowsquareshaped rod 66 attached to collar 61. Rod 66 extends through theupper end of mandrel 29 and connects to swivel 39. Collar 61 is providedwith a cam follower 62 which engages in a sawtooth" or Y-shaped camsurface or track 63 formed in the inner wall of mandrel 29. As seenparticularly in FIG. 6, track 63 is provided with hinged leaf springs 64at each juncture of the vertical paths of track 63 to permit camfollower 62 to travel and shaft 60 operably attached thereto to rotate,in only one direction, as indicated by the arrow. In the operation ofthis embodiment, fluid is circulated down pipe string 12 through bypassand up pipe string 13 to move swab cups and shaft 66 and collar 61 andcam follower 62 upwardly until cam follower 62 travels up to the upperportion of track 63. Then by gravity or by reverse circulation of fluiddown pipe string 13 through bypass 15 and up pipe string 12, swab cupsand collar 61 and cam follower 62 move down and into the next succeedingleg of each Y section as indicated. As collar 61 is rotated by thetravel of cam follower 62, rod 66 is rotated which in turn rotates shaft65 and shaft 60 attached to shaft 65.

As shown in FIG. 7 a pressure switch 70 is connected into thedetector-battery-gun circuit, generally designated 71, to ensure thatthe gun is only armed for firing at the depth at which it is to be used.Pressure switch 70 is preset for a selected hydraulic pressure in thepipe string.

Another safety precaution is shown in FIGS. 8 and 9. An overtravelswitch 75 is provided with a rod contact 76 which engages support member45 upon movement of that support member upwardly. It is designated toactuate just prior to separation of the splined keyway 40 and key shaft44 described with reference to FIG. 3. Housing 29 may be filled with anonconductive liquid when a slipring-type conductor is used. The circuitshown in FIG. 9 includes the pressure switch 70.

The perforating operation is illustrated in FIGS. 2A-2F. In FIG. 2A,radioactive or nuclear source tool 18 to which has been connected arunning tool 80, having oppositely facing swab cups 81 and releasableprongs 82 connected to running and retrieving head 24 of nuclear sourcetool 18, is launched in pipe string 12 and pumped through that pipestring until mandrel 21 is landed in landing nipple 16 to positionradioactive pill 19 at a predetermined level.

As shown in FIG. 2B, locomotive running tool 80 is retrieved by reversecirculating fluid down pipe string 13 through bypass 15 and up pipestring 12.

As shown in FIG. 2C, perforator tool 26 has been launched in pipe string13 and pumped through that pipe string until mandrel 29 is landed inlanding nipple 17 by circulating fluid down pipe string 13 throughbypass 15 and up pipe string 12 as indicated. Radiation detector 37 isthen located at a preselected depth at the same level as radioactivepill 19.

When it is desired to cause perforation of formation 11 fluid is pumpeddown pipe string 12 through bypass 15 and up pipe string 13 to movelocomotive device 27 upwardly and cause radiation detector 37 to rotatein accordance with the operation described with respect to FIG. 3.Either of the other two techniques illustrated and described withrespect to FIGS. 4 and 5 may also be used to cause rotation of detector37. As illustrated in FIG. 2D, when detector window 38 is facingradioactive pill 19, electrical power is applied to firing head 35 tocause gun elements 36 to fire. As indicated by the simple circuits shownin FIGS. 7 and 9, sufficient pressure must exist to actuate pressureswitch to complete the circuit (FIG. 7) and if the overtravel switch isused, then that switch must also be actuated to complete the circuit asillustrated in FIG.

As illustrated in FIG. 2E, perforator tool assembly 26 is circulatedfrom pipe string 13 by pumping fluid down pipe string 12 through bypass15 and up pipe string 13.

Nuclear source tool 18 is then retrieved by pumping a retrieving tool85, having oppositely facing swab cups 86 and prongs 87 for latchingonto retrieving head 24 of nuclear source tool 18, is pumped throughpipe string 12 until it latches onto nuclear source tool 18. Then, asillustrated in FIG. 2F, fluid is pumped down pipe string 13 throughbypass 15 and up pipe string 12 under sufficient pressure to causeshearable lugs 25 to shear to permit removal of nuclear source tool 18from pipe string 12.

Having fully described the apparatus, advantages, objects and method ofour invention, we claim:

1. A method for perforating in a tubingless TFL well containing twospaced apart, parallel pipe strings comprising:

launching a radioactive source into one of said pipe strings; pumpingsaid radioactive source through said one pipe string to adjacent a leveltherein at which it is desired to perforate;

launching into said other pipe string a perforating tool provided with aperforating gun having a selected direction of perforation, a detectorof radiation having a selected direction of radiation detection relativeto said direction of perforation, means for rotating said perforatinggun when said perforating tool is caused to move by hydraulic pressure,a locomotive device for causing said perforating tool to move throughand in said other pipe string by hydraulic pressure, aradioactivity-sensitive firing mechanism including a source ofelectrical power for actuating said perforating gun, and a switchactuatable when the radioactive count detected by said radiationdetector reaches a predetermined level;

pumping said perforating tool through said other pipe string until theradiation detector is at the level of said radiation pill; and

moving said perforating tool by circulation of fluid through saidpipestrings to cause the perforating gun to rotate until at one angularposition of said perforating gun the detected radiation by saidradiation detector reaches a preselected level to indicate that thedirection of detection of radiation is toward said radioactive pill andsaid direction of perforation is in a selected direction, saidperforating gun automatically firing when in such position.

2. A method as recited in claim 1 in which said direction of perforationis away from said one pipe string.

3. A method as recited in claim 1 in which said direction of perforationis toward said one pipe string.

4. A method as recited in claim 1 in which said perforating gunautomatically firing when in said one angular position when wellpressure adjacent said perforating tool is at a predetermined level.

5. A method as recited in claim 4 in which movement of said perforatingtool by circulation of fluid to cause the perforating gun to rotate alsoactuates a switch to permit said perforating gun to fire.

6. A method as recited in claim 1 including the step of reversecirculating said perforating gun out of said other pipe string afterfiring of said perforating gun.

7. A method as recited in claim 6 wherein said perforating tool is movedupwardly to cause said perforating gun to rotate.

8. A method as recited in claim 6 including moving said perforating toolupwardly and downwardly to cause said perforating gun to rotate.

9. Apparatus for perforating in a tubingless TFL well containing twospaced apart, parallel pipe strings connected together through acrossover port comprising:

a pumpable perforating tool adapted to be pumped into and out of one ofsaid pipe strings and provided with a perforating gun having a selectedangular direction of perforation and a detector having a selectedangular direction of radiation detection relative to said direction ofperforation, locomotive means for causing said perforating tool to movevertically in one of said pipe strings when acted upon by hydraulicpressure, rotating means

1. A method for perforating in a tubingless TFL well containing twospaced apart, parallel pipe strings comprising: launching a radioactivesource into one of said pipe strings; pumping said radioactive sourcethrough said one pipe string to adjacent a level therein at which it isdesired to perforate; launching into said other pipe string aperforating tool provided with a perforating gun having a selecteddirection of perforation, a detector of radiation having a selecteddirection of radiation detection relative to said direction ofperforation, means for rotating said perforating gun when saidperforating tool is caused to move by hydraulic pressure, a locomotivedevice for causing said perforating tool to move through and in saidother pipe string by hydraulic pressure, a radioactivity-sensitivefiring mechanism including a source of electrical power for actuatingsaid perforating gun, and a switch actuatable when the radioactive countdetected by said radiation detector reaches a predetermined level;pumping said perforating tool through said other pipe string until theradiation detector is at the level of said radiation pill; and movingsaid perforating tool by circulation of fluid through said pipe stringsto cause the perforating gun to rotate until at one angular position ofsaid perforating gun the detected radiation by said radiation detectorreaches a preselected level to indicate that the direction of detectionof radiation is toward said radioactive pill and said direction ofperforation is in a selected direction, said perforating gunautomatically firing when in such position.
 2. A method as recited inclaim 1 in which said direction of perforation is away from said onepipe string.
 3. A method as recited in claim 1 in which said directionof perforation is toward said oNe pipe string.
 4. A method as recited inclaim 1 in which said perforating gun automatically firing when in saidone angular position when well pressure adjacent said perforating toolis at a predetermined level.
 5. A method as recited in claim 4 in whichmovement of said perforating tool by circulation of fluid to cause theperforating gun to rotate also actuates a switch to permit saidperforating gun to fire.
 6. A method as recited in claim 1 including thestep of reverse circulating said perforating gun out of said other pipestring after firing of said perforating gun.
 7. A method as recited inclaim 6 wherein said perforating tool is moved upwardly to cause saidperforating gun to rotate.
 8. A method as recited in claim 6 includingmoving said perforating tool upwardly and downwardly to cause saidperforating gun to rotate.
 9. Apparatus for perforating in a tubinglessTFL well containing two spaced apart, parallel pipe strings connectedtogether through a crossover port comprising: a pumpable perforatingtool adapted to be pumped into and out of one of said pipe strings andprovided with a perforating gun having a selected angular direction ofperforation and a detector having a selected angular direction ofradiation detection relative to said direction of perforation,locomotive means for causing said perforating tool to move vertically inone of said pipe strings when acted upon by hydraulic pressure, rotatingmeans for rotating said perforating tool when said perforating tool ismoved vertically in said one pipe string by hydraulic pressure, andmeans for automatically firing said perforating gun when the level ofradiation detected is at a preselected value; and a radiation sourceadapted to be pumped into and out of said other pipe string. 10.Apparatus as recited in claim 9 including means arranged on saidperforating tool adapted to prevent firing of said perforating gun untila predetermined pressure is reached in said one pipe string at the levelof said perforating tool.